求助，没有用队列，用了数组模拟，爆了几个点

#include<bits/stdc++.h>
using namespace std;
int m, n, t, tail;
bool con = true;
int sen[1010];
vector<int> ram;
int main() 
{
	cin >> m >> n;
	for (int i = 1; i <= n; i++) cin >> sen[i];
	for (int i = 1; i <= n; i++) 
	{
		con = true;
		if (ram.size() == m) 
		{
			tail++;
			m++;
		}
		for (int j = tail; j < ram.size(); j++) 
		{
			if (ram[j] == sen[i]) 
			{
				con = false;
				break;
			}
		}
		if (con) 
		{
			t++;
			ram.push_back(sen[i]);
		}
	}
	cout << t << endl;
	return 0;
}